• Journal of Microbiology and Biotechnology
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• v.23 no.2
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• pp.211-217
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• 2013

Corynebacterium glutamicum is one of the well-studied industrial strain that is used for the production of nucleotides and amino acids. Recently, it has also been studied as a possible producer of organic acids such as succinic acid, based on its ability to produce organic acids under an oxygen deprivation condition. In this study, we conducted the optimization of medium components for improved succinate production from C. glutamicum under an oxygen deprivation condition by Plackett-Burman design and applied a response surface methodology. A Plackett-Burman design for ten factors such as glucose, ammonium sulfate, magnesium sulfate, potassium phosphate ($K_2HPO_4$ and $KH_2PO_4$), iron sulfate, manganese sulfate, biotin, thiamine, and sodium bicarbonate was applied to evaluate the effects on succinate production. Glucose, ammonium sulfate, magnesium sulfate, and dipotassium phosphate were found to have significant influence on succinate production, and the optimal concentrations of these four factors were sequentially investigated by the response surface methodology using a Box-Behnken design. The optimal medium components obtained for achieving maximum concentration of succinic acid were as follows: glucose 10 g/l, magnesium sulfate 0.5 g/l, dipotassium phosphate ($K_2HPO_4$) 0.75 g/l, potassium dihydrogen phosphate ($KH_2PO_4$) 0.5 g/l, iron sulfate 6 mg/l, manganese sulfate 4.2 mg/l, biotin 0.2 mg/l, thiamine 0.2 mg/l, and sodium bicarbonate 100 mM. The parameters that differed from a normal BT medium were glucose changed from 40 g/l to 10 g/l, dipotassium phosphate ($K_2HPO_4$) 0.5 g/l changed to 0.75 g/l, and ammonium sulfate ($(NH_4)_2SO_4$) 7 g/l changed to 0 g/l. Under these conditions, the final succinic acid concentration was 16.3 mM, which is about 1.46 fold higher than the original medium (11.1 mM) at 24 h. This work showed the improvement of succinate production by a simple change of media components deduced from sequential optimization.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.260-266
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• 1996

This study was carried out to investigate the bacterial microflora of commercial and traditional Kochujang. Computer aided idetification systems were used to identify the bacteria in Kochujang. Seven genera such as Bacillus, Corynebacterium, Enterococcus, pasteurella, Pseudomonas, Staphylococcus and Streptococcus in commercial process and 10 genera such as Bacillus, Corynebacterium, Enterococcus, Flavimonas, Flavobacterium, Gemella, Pasteurella, Pseudomonas, Staphylococcus and Streptococcus in traditional process were identified. Distribution of genus Bacillus was $56{\sim}70%$ during fermentation in the commercial process and $38{\sim}50%$ in the traditional process. B. lichenoformis strains identified in this study were classified into three types by their physiological characteristics.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.840-845
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• 2011

Degradation products of agarose are biologically active and thus used as an ingredient in pharmaceuticals or functional cosmetics. Furthermore, it has been strongly considered as a substrate for bio-ethanol fermentation. Recently, we isolated new agarase-producing microorganism, Pseudoalteromonas sp. from south sea of Korea. In this study, we aimed to separate and purify the agarase from culture broth of this strain. Separation of agarase was performed by ion- exchange chromatography on DEAE-Sepharose resin. Equilibrium pH and volume ratio of resin to the amount of protein were optimized for the efficient adsorption of protein. 410 ${\mu}g$ of protein was completely adsorbed to 3 mL of resin at pH 7.5. The total amount of eluted protein increased as NaCl concentration increased to 400 mM at isocratic elution. Agarase was separated by linear gradient elution of NaCl (0~1,000 mM). Three major protein peaks were observed and the presence or absence of agarase in these eluted proteins was measured by Lugol's staining technique. Only six eluted protein fractions showed strong agarase activity.

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.389-394
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• 2003

In order to screen microorganisms producing phopholipase D (PLD) had high transphosphatidylation activity, about 1,000 Actinomycetes strains were isolated from the 63 soil samples, collected over 6 local area in Korea. When the hydrolytic activity in the supernatant was determined, 131 strains produced PLD more than 0.3 U/ml. Among 131 culture broths tested, 23 ones had transphosphatidylation activity higher than 20% and finally one strain (Actinomycetes KF 923), which had highest hydrolytic and transphophadylation activity, was selected. Actinomycetes KF923 showed the highest hydrolytic activity (13 U/ml) and phosphatidylation activity (95%) after 48 h fermentation using the P medium (yeast extract 1%, peptone 1%, glucose 1.5%, glycerol 1%, $CaCo_3$ 0.4%, pH 7.2). PLD was purified from the culture broth of Actinomycetes KF923 and the specific activity of purified PLD was 567 U/mg. The molecular weight of PLD was about 55 kD and the optimum pH and temperature were 6.0 and $60^{\circ}C$, respectively. The stability of PLD toward pH and temperature were high around pH 8.0 and below $40^{\circ}C$. Special metal ions were not necessary to the PLD activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.411-416
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• 2002

Yogurt base was prepared from whole milk and skim milk added with 0.2∼1.0% (w/v) of Saururus chinensis(Lour.) Bail water extract (SCe) and fermented with lactic acid bacterias (the mixed strain of Streptococcas themophilus and Lactobacillus bulgaricus) at 37$\^{C}$ for 24 hr. Quality characteristics of the yogurt were evaluated in terms of acid production, number of viable cells, viscosity and sensory property during lactic acid fermentation. The composition of organic acids was also measured by HPLC. Addition of SCe stimulated the growth of lactic acid bacteria and remarkably enhanced the acid production. The viscosity and lactic acid content of yogurt were also increased by addition of SCe. The sensory score of yogurt added with 0.4% of SCe was significantly higher than other groups in taste and overall acceptability The storage abilities of yogurts added with SCe were relatively good at 5$\^{C}$ for 15 days.

• Research in Plant Disease
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• v.18 no.2
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• pp.109-116
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• 2012

A bacterial strain antagonistic to some fungal phytopathogens was isolated from the stem of a Persimmon tree in Yeongam, Korea. This bacterium was identified as Bacillus subtilis by 16S rRNA gene sequencing and designated as B. subtilis GDYA-1. In in vivo experiment, the fermentation broth exhibited antifungal activities against Magnaporthe oryzae on rice plants, Phytophthora infestans on tomato plants, and Puccinia recondita on wheat plants. We isolated one antifungal compound and its chemical structure was determined by mass and $^1H$-NMR spectral data. The antifungal substance was identified as benzoic acid. It inhibited mycelial growth of M. oryzae, Rhizoctonia solani, Sclerotinia sclerotiorum, and P. capsici with minimum inhibition concentration (MIC) values, ranging from 62.5 to 125 ${\mu}g/ml$. Moreover, the substance effectively suppressed Phytophthora blight of red pepper caused by P. capsici in a pot experiment. To the author's knowledge, this is the first report on the antifungal activity of benzoic acid against phytopathogenic fungi. Benzoic acid and B. subtilis GDYA-1 may contribute to environmental-friendly protect crops from phytopathogenic fungi.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.328-333
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• 2014

Folate is a water-soluble vitamin B that is required for the synthesis of amino acids and nucleic acids. It plays an important role in cell division and cell growth in several living organisms. The purpose of this study was to screen strong folate-synthesizing bacteria and to optimize their culture conditions for folate production. Folate production was quantified by microbiological assays by using folate-dependent strain Lactobacillus rhamnosus KCTC 3237. Folate derivatives were identified by LC-MS/MS. Of the 65 strains of bifidobacteria and lactobacilli tested, L. plantarum Fol 708 demonstrated the greatest ability to produce folate. Its optimal pH for folate production was 5.5 in a pH-controlled, lab-scale fermenter. Coculturing L. plantarum Fol 708 with L. brevis GABA 100 in a milk medium enhanced the level of folate produced in comparison to culturing L. plantarum Fol 708 alone.

• The Korean Journal of Food And Nutrition
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• v.27 no.1
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• pp.43-49
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• 2014

Panax ginseng C.A. Meyer has been used as a traditional medicinal ingredient and the ginseng flower-buds also proved to have good medicinal properties. In this study, in order to enhance immune activities of ginseng flower-bud, the ginseng flower-bud extract was being fermented by Bacillus subtilis KCTC 1022 (BS), Lactobacillus plantarum KCTC3 and Saccharomyces cerevisiae strain CHY1011 (SC). Mice were orally administered daily for two weeks at two different concentrations (100 and 200 mg/kg B.W.). Treatment samples were water extracts of ginseng flower-buds (FD), water extracts of fermented ginseng flower-buds (FM) and controls for saline solution. Cytokine production (IL-6, TNF-${\alpha}$) either stimulated with LPS or not stimulated with LPS was detected by the ELISA assay when using the cytokine kit. Cytokine was statistically increased at supplemented groups with LPS in both the 100 and the 200 mg/kg B.W. and treatment with FM significantly decreased the LPS-induced TNF-${\alpha}$ and IL-6 production more than the treatment with FD. The results of this study may suggest that supplementation with FM increases the immune function by regulating cytokine production capacity for activated macrophages.

• Food Engineering Progress
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• v.14 no.1
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• pp.65-74
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• 2010

Culture conditions of L. plantarum TJ-LP-002, the garlic resistant strain isolated from pakimchi (green onion kimchi), were investigated for the use of feed additives. Acetic acid, citric acid, lactic acid, and tartaric acid were detected in the culture supernatant, and especially the concentrations of lactic acid and acetic acid significantly increased during cultivation. The antimicrobial activity of L. plantarum TJ-LP-002 was not affected by proteases, calatase or cellulase, which showed that the antimicrobial activity might be due to the production of acids rather than proteinaceous antimicrobial substances. L. plantarum TJ-LP-002 was resistant to neomycin sulfate, spectinomycin dihydrochloride, and lincomycin hydrochloride, sensitive to streptomycin sulfate, and intermediate resistant to ampicillin trihydrate, chloramphenicol, erythromycin, tetracycline hydrochloride, and kanamycin sulfate. The optimum initial pH of medium, fermentation temperature and time for the cell growth and antibacterial activity were pH 7.0, 30${^{\circ}C}$ and 24hr, respectively. The optimal composition of culture medium for the cell growth and antimicrobial activity was 3%(w/v) glucose as a carbon source, 3%(w/v) yeast extract as a nitrogen source, and manganese sulfate and ammonium citrate as inorganic salts. The combinatorial supplementation of these inorganic salts, rather than sole addition as an inorganic salt, resulted in better antibacterial activity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.554-562
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• 2021

Lactobacillus plantarum SM4, a strain producing β-glucosidase, was isolated from kimchi and fermented with white Taraxacum coreanum to enhance the production of bioactive compounds. The total polyphenol content(TPC), total flavonoid content(TFC), radical scavenging activity(RSA), tyrosinase inhibitory activities(TIA), and collagenase inhibitory activities(CIA) were measured to evaluate the skin whitening and anti-wrinkle effects of the fermented product. The TPC of fermented white T. coreanum was 41.8±0.26 mg GAE/g DW, which was approximately two times higher than the hot-water extraction of 21.4±0.67 mg GAE/g DW. RSA, an indicator of antioxidant activity, was 65.6±4.7% in fermentation, which is four times higher than that of the hot-water extract. TAI and CAI, which are indicators of the whitening and anti-wrinkle effects, were 87.9±4.73% and 66.7±3.48%, respectively, which were 2.4 and 1.5 times higher than those of hot-water extraction. When comparing the UVA(320 nm) protection effects of fermented and hot-water extraction, the fermented white T. coreanum showed higher protection with an absorption rate of 64.7% and 15.2%, respectively. The white T. coreanum fermented product showed higher bioactive properties and improved skin whitening, anti-wrinkle, and UV protection effects through the production of β-glucosidase from L. plantarum SM4.